Piloted main flame burner with burner ribbons



J. H. FLYN N- 3,521,988

PILQTED MAIN FLAME BURNER WITH BURNER RIBBONS July 28, 1970 Filed March14, 1968 United States Patent US. Cl. 431-284 1 Claim ABSTRACT OF THEDISCLOSURE A longitudinal burner casing has a peripheral wall of whichadjacent Wall parts diverge substantially rectangularly from alongitudinal corner of the casing, and a longitudinal partition in thecasing dividing it into main and pilot gas compartments. Machined intothe casing corner is a longitudinal, diagonally inwardly directed,groove extending through the pilot compartment and having in thepartition a bottom with a median longitudinal through-slot to the maincompartment. Inserted in the groove and seated on the remaining bottomthereof are two spaced U-channels with pilot flame ribbons therein andmain flame ribbons clamped between the channels, with these channelsdividing the pilot compartment into sections with which they are incommunication through spaced holes in the respective channels.

This invention relates to ribbon burners in general, and to ribbonburners for producing high velocity main flame and piloting flamestherefor in particular.

A prior burner of the type with which the present in vention isconcerned has in its casing a longitudinal slot at the top which is opento the gas compartment therein and receives a main and pilot flame portassembly in the form of spaced U-channels holding pilot burner ribbons,and main burner ribbons which are clamped between the channels. With theslot being usually arranged to lie with its median plane in thelongitudinal plane of symmetry of the casing, and with the slot partingthe casing thereat over its entire length, the effect of peripheralexpansion of the casing throughout on heat-up of the burner in operationis particularly severe at the slot and demonstrates itself by highlyobjectionable gaping of the walls of the slot from the flame portassembly therein with ensuing gas leakage paths therethrough and unevenpilot as well as main flames over the length of the burner. Further,with the slot lying in the longitudinal plane of symmetry of the casingand being, moreover, of considerable depth to accommodate the U-channelswhich are usually of considerable height, especially in a burner casingin which they are to extend through a pilot gas compartment into atherefrom partitioned main gas compartment to seal the latter from theformer, the casing is sufliciently weakened structurally over thedepthwise extent of the slot there to bellmouth all too readily onforced insertion of the flame port assembly, also with ensuing gasleakage paths and uneven pilot and main flames over the length of theburner.

It is among the objects of the present invention to provide a burner ofthis type in which gas leakage paths 'through the slot in the burnercasing and the flame port assembly therein and ensuing uneven pilot andmain flames due to peripheral thermal expansion of the casing and/orbellmouthing of the slotted casing part, are eliminated.

It is another object of the present invention to provide a burner ofthis type in which the cross-sectional shape of the casing provides acorner which is formed by the junction of peripheral wall parts of thecasing that con- 3,521,988 Patented July 28, 1970 verge substantiallyrectangularly to each other, and the slot for the reception of the flameport assembly is machined into this corner of the casing throughout itslength and in an inward direction diagonal with respect to theconverging wall parts. -In thus arranging the casing and slot,peripheral expansion of the casing in operation of the burner occurs atthe slot in a direction inclined, preferably at angles of substantially45, to the slot walls, rather than substantially at right angles to theslot Walls as in the aforementioned prior burner, wherefore ensuinggaping of the opposite walls of the slot from the flame port assemblytherein is in any event much less than in this prior burner, and mayreadily be kept within limits at which for all practical intents andpurposes gas leakage paths through the slot and ensuing uneven flamesover the burner length are eliminated.

It is a further object of the present invention to provide a burner ofthis type in which the gas chamber in the casing is by a longitudinalpartition therein divided into main and pilot compartments of which thepilot compartment is next to the casing corner, and the aforementioneddiagonal slot for the reception of the flame port assembly is in theform of a groove which extends through the pilot compartment and has itsbottom machined in the partition, with this groove bottom having overits length and a mid-portion of its Width 21 through-slot to the maincompartment to leave bottom shoulders on the opposite groove walls, andthe U-shaped channels of the flame port assembly being forced to restwith their closed bottoms on these bottom shoulders. In thus arrangingthe casing slot and mounting the flame port assembly therein with thechannels resting on the bottom shoulders, the slot is further sealedagainst gas leakage therethrough,

0 especially from the main compartment, under any and all conditions,including peripheral expansion of the casing in operation of the burner.

Another object of the present invention is to provide a burner of thistype in which the aforementioned chamberdividing partition in the casingis at the slot therein also in the form of a corner at the junction ofconverging partition parts which preferably extend substantiallyparallel to the peripheral wall parts of the casing that join to formthe outer casing corner. With this arrangement, gaping of thesepartition parts from the flame port assembly therebetween on peripheralexpansion of the easing in operation of the burner may also readily bekept within limits at which for all practical intents and purposes gasleakage paths thereat and ensuing uneven flames over the burner lengthare eliminated.

It is a further object of the present invention to provide a burner ofthis type in which the aforementioned corner construction of the casingoutside and inside thereof is re-enforced to the point where this cornerstructure will, despite its parting by the slot therein, respond toperipheral expansion of the casing in burner operation unnoticeably ingaping from the inserted flame port assembly, and will respond to thetightest insertion of the flame port assembly equally unnoticeably inbellmouthing. This is achieved in particularly simple manner byproviding the preferably cast casing with sets of integral ribs, ofwhich the ribs of two sets extend in the pilot gas compartment andconnect the peripheral wall parts with the nearby partitionparts of theaforementioned corner structure of the casing on the opposite sides ofthe slot therein, and the ribs of a third set extend in the main gascompartment across the inner corner and tie together the partition partsconverging on this corner. With this arrangement, these partition partsare by the ribs in the main gas compartment held directly and mosteffectively against gaping from the inserted flame port assembly onperipheral casing expansion in burner operation, and the peripheral wallparts are by the ribs in the pilot gas compartment directly connectedwith the partition parts, with the overall result that the cornerstructure of the casing is, despite the slot therein, extremely rigidand will not effectively yield to stresses ensuing from peripheralcasing expansion or insertion of the flame port assembly into the slotin even particularly tight manner.

Further objects and advantages will appear to those skilled in the artfrom the following, considered in conjunction with the accompanyingdrawings.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

FIG. 1 is a front view of a burner embodying the present invention;

FIG. 2 is a side view of the burner;

FIG. 3 is a section through the burner taken substantially on the line33 of FIG. 1;

FIG. 4 is a fragmentary section through the burner taken on the line 44of FIG. 1;

FIG. 5 is a fragmentary section through the burner taken on the line 55of FIG. 2; and

FIG. 6 is a fragmentary top view of the burner.

Referring to the drawings, and more particularly to FIGS. 1 to 3thereof, the reference numeral 10 designates a burner having alongitudinal burner casing 12 With a chamber 14 and an internalpartition 16 which divides the chamber into main and pilot gascompartments 18 and 20. The casing 12 is preferably cast, with theperipheral wall 22, end walls 24 and partition 16 thereof being formedintegrally with each other. Provided in the casing 12 is a machined slot26 which extends longitudinally over the length of the casing 12 (FIG.5), and extends depthwise through the peripheral casing wall 22, pilotcompartment 20 and partition 16 (FIG. 3), and is adapted for thereception of a flame port assembly 28.

The part of the slot 26 in the peripheral casing wall 22 is in alongitudinal corner structure of the casing which is formed at thejunction of two converging peripheral casing wall parts 32 and 34 thatextend transversely, and preferably substantially rectangularly, to eachother. The slot 26 has a median plane p lying substantially in thecasing corner 30 and extending inwardly diagonally with respect to theconverging wall parts 32 and 34 (FIG. 3), with this median plane ppreferably forming with the wall parts 32, 34 angles A of substantiallyThe flame port assembly 28 comprises in this instance main flame ribbons36 and pilot flame ribbons 38 of any suitable kinds, as well as twoU-channels 40 and 42 with closed bottoms 44 (FIGS. 3 and 6). The pilotflame ribbons 38 are tightly fitted in the open tops of the channels 40and 42 and provide gas ports for feeding pilot flames thereat, while themain flame ribbons 36 are tightly clamped between the channels 40 and 42at the top and provide gas ports for feeding main flames thereat, withthe channels being, in turn, tightly clamped to the opposite side wallsof the slot 26 to thereby seal the pilot compartment 20 from the maincompartment 18 and also divide the pilot compartment 20 into sections 48and 50 which are, moreover, also sealed from each other by thesechannels 40, 42 which extend in the slot 26 within the thicknessconfines of both end walls 24 of the casing (FIG. 5). The flame portassembly just described is preferably preassembled into a self-containedunit before its forced insertion into the slot 26, and the channels 40,42 and burner ribbons 36, 38 are to this end held together bylongitudinally spaced crosspins 51. The channels 40 and 42 havelongitudinally spaced holes 52 through which to receive combustible gasfrom the respective pilot compartment sections 50 and 48 for feeding thepilot flames at the pilot ribbons 38, while the main flames at the mainribbons 36 are fed with combustible gas from the main compartment 18 viaslot 26 and the space s between the channels 40, 42. The slot 26 beyondthe opposite ends of the flame port assembly 28 therein is effectivelysealed from the main and pilot compartments 18 and 20 by suitablespacers 53 and 55 which are held in place by end caps 57 on the oppositecasing ends (FIGS. 1, 2 and 5).

The casing 16 is also provided with an inlet 56 to the main compartment18, with this inlet being through a conduit 58 connected with a usualmixer (not shown) in which gas and air is mixed into a combustible gaswith which the main compartment 18 is supplied. The casing 12 has inthis instance another inlet 60 to the pilot compartment section 48, withthis inlet 60 being through a conduit 62 connected with another mixer(not shown) which supplies combustible gas to the compartment section48. The gas conduit 58 also has an interposed valve (not shown) forquantitative regulation of the combustible gas to the main compartment18, and the gas conduit 62 may also have an interposed valve. The pilotcompartment section 58 is supplied with combustible gas directly fromthe main compartment 18, and the partition 16 is to this end providedwith an aperture 64 (FIG. 4). For regulation of the gas flow into thecompartment section 50, there is provided a valve plug 66 which isthreadedly received in the casing 12 as at 68 and extends toward theaperture 64. The valve plug 66 is adjustable from the outside of thecasing 12 to regulate the flow passage from the main compartment 18 intothe aperture 64, and the valve plug is locked in adjusted position by anut 70. Secured at 72 to a stud 74 in the main compartment 18 is abafile 76 which is in line with the gas inlet 56 and serves to divertthe instreaming combustible gas into a course substantiallylongitudinally of the main compartment for even distribution in thelatter.

Part of the slot 26 from its outer end through and beyond the pilotcompartment 20 is, by machining, widthwise enlarged equally on bothsides of the median plane p to form a groove 78 with opposite side walls80 and 82 and bottom shoulders 84 and 86 which are formed in thepartition 16 on opposite sides of the slot 26 therein. The purpose ofthe partial groove formation of the slot 26 is the provision of thebottom shoulders 84 and 86 which advantageously serve as rest shouldersfor the closed bottoms 44 of the channels 40 and 42, with these channelsbeing clamped sidewise tothe respective groove walls 80 and 82.

In operation of the burner, the casing 12 becomes heated from theissuing flames, and this will bring about peripheral expansion of thecasing. Such thermal peripheral casing expansion is of concern at thecasing slot 26 and the flame port assembly 28 therein, because ofensuing gaping, more or less, of the slot walls, and in this instance ofthe groove walls 80 and 82, from the adjacent channels 40, 42 of theflame port assembly which may give rise to gas leakage thereat that mayeffect the evenness of the flames over the burner length. However, dueto the casing corner structure 30 and the provision therein of thediagonally directed slot 26, thermal peripheral casing expansion bringsabout virtually negligible gaping of the opposite walls of the slot fromthe flame port assembly therein. This, thermal peripheral expansion ofthe casing at the slot 26 is primarily in the direction of the arrows9t), i.e., at angles of substantially 45 to the median plane 2 of theslot, wherefore actual gaping of the slot walls from the flame portassembly is but a fraction of the actual expansion displacement of theseslot walls. Further, regardless of gaping of the slot walls from theflame port assembly, gas leakage from the main compartment through theslot is effectively prevented by virtue of the rest of the channels 40,42 with their bottoms 44 on the bottom shoulders 84, 86 in the slot.

To keep gaping of the slot walls from the flame port assembly in thermalperipheral casing expansion at a minimum which to all practical intentsand purposes is negligible and does not affect the evenness of theflames throughout the burner length, the partition 16 is at the slot 26therein also formed as an inner corner structure 92 of the casing. Tothis end, the corner 92 is formed by the junction of two convergingpartition parts 94 and 96 which are inwardly spaced from, and extendsubstantially parallel to, the peripheral wall parts 32 and 34,respectively, of the casing, with the median plane p of the slot 26lying substantially in both casing corners 30 and 92 (FIG. 3).

In order to keep gaping of the slot walls from the flame port assemblyon thermal peripheral casing expansion at an absolute minimum at whichflames from many burners operating at maximum capacity have beenobserved to be and remain entirely even throughout the burner length,and also to prevent any possible bellmouthing of the slotted casing parton driving the flame port assembly into the slot even with aparticularly tight fit, the casing 12 is also provided with series oflongitudinally spaced, integral ribs 98, 100 and 102 (FIGS. 3 and 5).The ribs 98 extend transversely of the casing 12 and connect theperipheral wall part 34 with the partition part 96 next to the slot 26,whereby these parts 34 and 96 are strongly tied together into a highlyrigid structure. Similarly, the ribs 100 extend transversely of thecasing and connect the peripheral wall part 32 with the partition part94 next to the slot 26, whereby these parts 32 and 94 are also tiedtogether into a highly rigid structure. Finally, the ribs 102, whichalso extend transversely of the casing, connect the partition parts 94and 96 across and next to the inner casing, corner 92. With these ribformations 98 to 102, the casing structure at and in the vicinity of theslot 26 is re-enforced and its rigidity increased so highly thatbellmouthing of the casing thereat is avoided even at the tightest fitof the flame port assembly in the slot, and whatever slight gaping ofthe slot walls from the flame port assembly may occur on thermalperipheral casing expansion in burner operation at maximum capacity forany length of time, this will assuredly have no eflect whatsoever on theevenness of the flames throughout the burner length.

The invention may be carried out in other specific Ways than thoseherein set forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein,

What is claimed is:

1. A burner, comprising a longitudinal casing having a chamber, aperipheral Wall and a longitudinal partition dividing the chamber intomain and pilot gas compartments, with parts of said wall defining partof said pilot compartment and converging on each other substantiallyrectangularly to each other to form at their junction an outerlongitudinal corner on the casing, and parts of said partition beingspaced from, and extending substantially parallel to, said converging,wall parts and converging on each other to form at their junction aninner longitudinal corner on the casing, and said casing having in saidconverging wall parts and partition parts a longitudinal groove withopposite parallel side walls and a bottom wall, of which the side wallsextend into, and said bottom wall is in, said converging partitionparts, with said groove having a median plane lying substantially insaid outer and inner casing corners, and said bottom wall having midwayof its width a slot extending through said converging partition partsand being of smaller width than said groove to leave at said bottom wallspaced opposite bottom shoulders, and sets of integral ribs, of whichthe ribs of all sets are longitudinally spaced and extend transverselyof the casing, with the ribs of two sets extending from said convergingwall parts to said converging partition parts on opposite sides,respectively, of said groove, and the ribs of another set projectingfrom said partition parts into said main compartment and extendingacross said slot, and a flame port assembly fitted in said grooveincluding two U-channels spaced from each other and abutting said sidewalls and bottom shoulders of said groove to seal said pilot compartmentfrom said main compartment and divide said pilot compartment into twosections sealed from.

each other.

References Cited UNITED STATES PATENTS 2,428,274 9/ 1947 Flynn et al.43l278 2,748,848 6/1956 Flynn 431-284 EDWARD G. FAVORS, Primary ExaminerUS. Cl. X.R. 239553.

